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Transcript of Devils Tower
Rises over the northeastern edge of Wyoming at 867 feet tall.
Explained to be a sedimentary rock formation, that was intruded by magma that welled towards Earth’s surface.
Devils Tower was announced as the first national monument in 1906 by President Theodore Roosevelt.
Many northern plain tribes have worshiped this geological monument for thousands of years.
Layers of the Tower
Local Geology and Wildlife
By Jaelyn Daluraya
The Spearfish Formation
The oldest visible rock.
Was laid in a shallow sea 225 to 195
million years ago.
Is a dark red sandstone and maroon
Oxidation from iron causes the redness
of the rock.
Is similar to the ones at the Belle Fourche
Second oldest rock layer.
Deposited around 195 to 136 million years ago.
Is a thin band of white gypsum.
Gypsum Springs Formation
The Stockade Beaver member
Was deposited 195 to 136 million years ago.
Is a combination of gray-green shale, fine-grain sandstone, limestone, and red mudstone.
The Hulett Sandstone member
Deposited 195 to 136 million years ago.
Is a yellow, fine-grain sandstone.
Resistant to weathering.
Forms the vertical cliffs around the tower.
Theories of How Devils Tower Formed
Geologists are certain Devils Tower was formed from and intrusion, but wonder when the process started and if the magma reached the surface:
Magma welled to the surface, intruding the existing sedimentary rock layers around 50 to 60 million years ago.
May be an eroded remnant of a laccolith.
Could be a volcanic plug or the neck of an extinct volcano.
Can also be a stock.
The magma that formed Devils Tower cooled and crystallized into phonolite porphyry. The rock cooled and contracted into hexagonal columns. These columns are similar but larger than the ones in Devil's Potspile in California.
Thank You For Listening!
Surrounds grasslands and the Ponderosa pine forests.
At the top of the tower are many grassy meadows with many burrows.
About 1,200 black-tailed prairie dogs.
There are rats, mice, ants, and even snakes.
Overall, Devils Tower is an amazing geological formation.
Devils Tower was worshiped by many tribes and is called home to many local plants and animals. The formation of this tower was very fascinating to learn about and I hope you learned something new too!
Selbert, Pamela. "Devils Tower national monument: on the northeastern edge of Wyoming lies the famous monolith that mythically and geographically lends itself to awe." Trailer Life Oct. 2010: 18+. General Reference Center GOLD. Web. 24 Feb. 2014.